The words “too little” are an insertion of the King James Version Render rather, “the border of the children of Dan was extended.” The Hebrew appears to mean “the children of Dan enlarged their border because they had not room enough.”
The reason of this was that the Danites, a numerous tribe (Numbers 26:5 note), found themselves Judges 1:34-35 cooped up among the hills by the powerful and warlike Amorites. Hence, the Danite expedition (see the marginal reference), which surprised the Sidonion inhabitants of Leshem, an unwarlike and peaceable race, exterminated them, and annexed their city and territory to the portion of Dan.